I will be replacing brake pads (and either machining the rotors or replacing them) on my wife’s 2007 Dodge Grand Caravan and my 2008 Pontiac G6. I purchased the Haynes repair manuals for each vehicle. In both cases, the Haynes manual tells me to remove two-thirds of the brake fluid before beginnin…

Where does the displaced fluid go when you crank down the C clamp, do you open up the bleeder and drain it through a hose that way into a container? If the brake fluid hasn’t been flushed for a couple years, this might be a good time to do this.

Yes, you MUST remove the brake fluid from the master cylinder, or have the brake bleeder valve open when you are compressing the pistons back into the caliper body. The reason for this is to remove the brake fluid that has been contaminated with dirt, road grime, oils, and most importantly, water, …

It went back in to the master, if you haven’t added any fluid, then there is room, since it was full when the pads were new and the piston out. This is what I used to do, too. Since new brakes are a good time for new fluid, open the bleeder, then when it comes to pump time, pump through new fluid …

BC, Thanks for your info. So water, dirt, and road grime can get into the brake fluid? I assumed that this part of the brake system is a “closed” system. How do contaminants get into the fluid?

The darker your brake fluid coming out the bleeder, the more contaminated it is. Keep bleeding it until it looks like the new clear stuff coming out of the bottle.

Brake fluid sucks water in from the air anytime you open the cap on the reservoir, plus most reservoir caps do not make an air tight seal. Rust, bits of metal, and bits of seals from the brake system itself also wind up in the fluid over time.

Its not a completely closed system. Just very well sealed. Most of the stuff that gets into the brake system is actually transferred from the brake caliper piston into the caliper. Usually done when the pistons are squeezed back into the caliper. As the pads wear, more of the piston is exposed to …

When replacing brake pads, you should ALWAYS open the bleeder on the caliper when retracting the piston. You do NOT want to force old brake fluid back into the master or ABS system. Discard the old fluid that drains out the bleeders and refill the master with FRESH fluid which will then refill the c…

Thanks to all for your information!

Remove fluid during brake job

Maintenance/Repairs

Dingo1 October 28, 2010, 7:31pm 4

I never opened any “bleeder” for the fluid. I never considered where the fluid goes when compressing the caliper piston with a c clamp. I guess I assumed that it goes into the brake fluid reservoir. As I said, I completed a brake job in the past without removing any fluid from the reservoir.

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Remove fluid during brake job

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